Mechanical inertial igniters for reserve batteries and the like for munitions

Abstract

A device including: an impact mass movably restrained relative to a base; and a release mechanism configured to be movable between a restrained position for preventing movement of the impact mass and a released position for permitting movement of the impact mass when the release mechanism is subjected to an acceleration greater than a predetermined magnitude and duration; wherein the release mechanism having a release mass movable when subjected to the acceleration, the movement of the release mass not being influenced by movement of the impact mass.

What is claimed is: 
     
       1. A device comprising:
 an impact mass movably restrained relative to a base; and 
 a release mechanism configured to be movable between a restrained position for preventing movement of the impact mass and a released position for permitting movement of the impact mass when the release mechanism is subjected to an acceleration greater than a predetermined magnitude and duration the release mechanism having a release mass movable when subjected to the acceleration; 
 wherein the release mechanism is configured such that a force is not applied from the impact mass to the release mass when the impact mass is subjected to the acceleration. 
 
     
     
       2. The device of  claim 1 , wherein the release mass is separated from the impact mass in a lateral direction relative to a direction of the acceleration. 
     
     
       3. The device of  claim 1 , wherein the impact mass is rotatably movable relative to the base. 
     
     
       4. The device of  claim 1 , further comprising a flame producing means for outputting a flame upon movement of the impact mass. 
     
     
       5. The device of  claim 4 , wherein the flame producing means comprises:
 a first protrusion provided to protrude from a surface of the impact mass; 
 a second protrusion provided to protrude from the base, the second protrusion being positioned such that movement of the impact mass causes contact between the first and second protrusions; 
 a pyrotechnic provided proximate to one of the first and second protrusions such that the contact between the first and second protrusions ignites the pyrotechnic; and 
 an opening in the base for outputting the flame from the base. 
 
     
     
       6. The device of  claim 1 , further comprising a biasing member for biasing the impact mass in a direction opposite to the direction of the acceleration. 
     
     
       7. The device of  claim 1 , further comprising a circuit for one of opening or closing an electrical circuit upon movement of the impact mass. 
     
     
       8. The device of  claim 7 , wherein the circuit comprises:
 an electrically conductive member provided to a surface of the impact mass; and 
 first and second electrical contacts, electrically isolated from each other, provided to the base, the first and second electrical contacts being positioned such that movement of the impact mass causes the electrically conductive member to contact and close the electrical circuit between the first and second electrical contacts. 
 
     
     
       9. The device of  claim 7 , wherein the circuit comprises:
 an electrically non-conductive member provided to protrude from a surface of the impact mass; and 
 first and second electrical contacts, electrically connected to each other, provided to the base, the first and second electrical contacts being biased in an electrically closed position and movable to an electrically open position, the first and second electrical contacts being positioned such that movement of the impact mass causes the electrically non-conductive member to move the first and second electrical contacts to the electrically open position. 
 
     
     
       10. The device of  claim 1 , wherein the release mechanism comprises:
 a shaft having one end engaged with a portion of the impact mass and an other end engaged with the release mass, the shaft being movable to the released position upon movement of the release mass when the release mass is subjected to the acceleration; and 
 a shaft biasing element for biasing the shaft into the released position when the release mass moves and is no longer engaged with the other end of the shaft. 
 
     
     
       11. The device of  claim 10 , further comprising a release mass biasing element for biasing the release mass into a position of engagement with the other end of the shaft. 
     
     
       12. The device of  claim 10 , wherein the release mass moves in translation. 
     
     
       13. The device of  claim 10 , wherein the release mass moves in rotation. 
     
     
       14. The device of  claim 1 , further comprising a housing including the base. 
     
     
       15. A method for moving an impact mass upon the impact mass experiencing an acceleration greater than a predetermined magnitude and duration, the method comprising:
 movably restraining the impact mass relative to a base;
 moving a release mechanism between a restrained position for preventing movement of the impact mass and a released position for permitting movement of the impact mass when the release mechanism is subjected to the acceleration; 
 configuring the release mechanism to have a release mass movable when subjected to the acceleration, wherein the release mechanism does not apply a force to the release mass when the impact mass is subjected to the acceleration. 
 
 
     
     
       16. The method of  claim 15 , further comprising separating the release mass from the impact mass in a lateral direction relative to a direction of the acceleration. 
     
     
       17. The method of  claim 15 , further comprising outputting a flame upon movement of the impact mass. 
     
     
       18. The method of  claim 15 , further comprising one of opening or closing an electrical circuit upon movement of the impact mass. 
     
     
       19. The method of  claim 15 , wherein the release mass moves in translation. 
     
     
       20. The method of  claim 15 , wherein the release mass moves in rotation.